| 单词 | secular variation |
| 释义 | > as lemmassecular variation a. Astronomy. Chiefly of changes in the orbits or the periods of revolution of the planets, as in secular acceleration, secular equation, secular inequality, secular variation. The terms secular acceleration, secular variation were formerly also used (with reference to the sense ‘century’ of Latin sæculum) for the amount of change per 100 years; similarly †secular precession (see quot. 1812). secular equation is also used more widely to designate any equation of the form |aij−bijλ| = 0 (i,j = 1,2, .., n), in which the left-hand side is a determinant and which arises in quantum mechanics. ΘΚΠ the world > time > duration > [adjective] > long-lasting or enduring > of processes of change secular1801 1801 Monthly Rev. 35 537 M. De La Place..found the secular equation of the moon to be due to the action of the sun on the moon. 1812 R. Woodhouse Elem. Treat. Astron. ix. 63 The secular precession, that is, the accumulated precessions of 100 years. 1814 J. Playfair Outl. Nat. Philos. II. ii. iii. 275 In the orbit of Mars, the eccentricity is diminishing. The secular variation of the greatest equation of the centre is—37″. 1834 M. Somerville On Connexion Physical Sci. (1849) iii. 16 Secular inequalities. 1862 A. Cayley Coll. Math. Papers (1890) III. 522 On the Secular Acceleration of the Moon's Mean Motion. 1937 E. C. Kemble Fund. Princ. Quantum Mech. x. 361 Its components must yield a nontrivial (i.e., nonvanishing) solution of the set of g equations Σn(Amn − aδmn)xn = 0... Such a solution exists only if the determinant of the coefficients vanishes, i.e., if a is a root of the so-called ‘secular’ equation det (A − aI) = ..0. 1974 G. B. Gill & M. R. Willis Pericyclic Reactions i. 21 To obtain the wave functions corresponding to these energies it is necessary to solve the secular equations using the appropriate values of E. < as lemmas |
| 随便看 |
|
英语词典包含1132095条英英释义在线翻译词条，基本涵盖了全部常用单词的英英翻译及用法，是英语学习的有利工具。